Experiments and Constitutive Modeling of the Magnetic Particle Fraction Dependence on Magneto‐Active Polymer Responses

Magneto‐active polymers (MAPs) are composite materials composed of a polymeric matrix (specifically, an elastomer) embedded with magnetic particles. When subjected to an external magnetic field, these materials change shape, volume, and magneto‐mechanical properties. In this work, we fabricate MAPs by embedding carbonyl iron particles into PDMS, with particle volume fractions ranging from 0% to 40%. We perform experiments to characterize the magneto‐mechanical responses of MAPs, followed by microstructural analysis. Motivated by experiments, we further develop a filler‐dependent coupled magneto‐mechanical constitutive model. The model is then calibrated using a minimal set of filler fractions and magnetic field data. Moreover, the model requires a few material parameters to simulate various coupled MAP responses effectively. Finally, the model is validated with the remaining experimental data and is ready to predict stress variations across different combinations of filler concentrations and magnetic fields under various loading conditions.